Ortho-carbalkoxy and ortho, ortho&#39;-dicarbalkoxy azo dyes containing or-tho-dihydroxy-phenyl or para-dihydroxy-phenyl groups



ORTHO-CARBALKOXE AND ORTHO .ORTI-IO' E M. IDELSON ETAL 3,336,287

-DICARBALKOXY AZO DYES CONT'AINI NG ORTHO DIHYDROXY PI-IENYL 0 PARA-DIHYDROXY-PHENYL GROUPS Filed Dec. 16, 1964 SUPPORT IMAGE-RECEIVING LAYER RUPTURABLE CONTAINER HOLDING A PROCESSING COMPOSITION slLv'ER HALIDE EMULSION LAYER AND ASSOCIATED TEMPORARILY 'SHYIFTED DYE DEVELOPER SUPPORT fLAYER OF PROCESSING COMPOSITION BLUE-SENSITIVE EMULSION AND IMAGE-RECEIVING LAYER 4%:7 ASSOCIATED YELLOW DYE DEVELOPER 50A Y .GREEN-SENSITIVE EMULSION AND 544 ASSOCIATED .TEMPORARILY SHIFTED' A -MAGENTA-D.YE DEVELOPER I 58 4 \{RED-SENSITIVE EMULSION AND ASSOCIATED cYAN DYE DEVELOPER SUPPORT LLI ' INVENTORQ WAVELENGTH IN MILLIMICRONS A ATTORNEYS) United States Patent 3,336,287 ORTHO-CARBALKOXY AND 0RTH0,0RTHO'-Dl- CARBALKOXY AZO DYES CONTAINKNG OR- THO DliHYDROXY PHENYL 0R PARA DIHY- DROXY-PHENYL GROUPS Elbert M. Idelson, Newton, and Howard G. Rogers, Weston, Mass., assignors to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed Dec. 16, 1964, Ser. No. 418,629 5 Claims. (Cl. 260---202) This invention relates to photography and, more particularly, to an improvement in photographic diffusiontransfer reversal processes for obtaining color images.

This application is in part a continuation of our copending US. application Ser. No. 788,892, filed Ian. 26, 1959 (now abandoned).

The copending US. application of Howard G. Rogers, Ser. No. 789,080, filed Jan. 26, 1959, and now abandoned, discloses and claims diffusion-transfer reversal processes employing a photosensitive element, comprising not less than one silver halide emulsion having associated therewith not less than one image-forming component having a temporarily shifted light-absorption spectrum. The photosensitive element may be exposed to a predetermined actinic energy pattern and the resultant latent silver halide image or images formed thereby developed in said emulsion or emulsions to effect, as a result of development, immobilization of the respective associated image-forming components in the exposed areas of said photosensitive element. An imagewise distribution of mobile imageforming components is thus provided in the unexposed areas of said photosensitive element which may be, at least in part, transferred by imbibition from the unexposed areas to a superposed image-receiving layer. A non-reversible restoration of at least a portion of the temporarily shifted image-forming components to their original spectral absorption characteristics is effected, at some stage subsequent to exposure, so as to impart to the imagereceiving layer a reversed positive dye image of the latent image exhibiting the desired spectral absorption characteristics.

It is a primary object of the present invention to provide novel photographic diffusion-transfer reversal processes and novel products for utilization therein.

Another object of the present invention is to provide novel photosensitive elements, comprising not less than one silver halide emulsion and not less than one dye developer, possessing increased emulsion speed and improved exposure control.

A further object of the present invention is to provide novel photographic compounds, processes and products for obtaining color images by diffusion-transfer reversal processes, wherein the light absorption characteristics of the dye developers utilized to provide said color images are temporarily shifted so that said dye developers absorb actinic energy at wave lengths substantially shorter during exposure than the wave lengths of the respective dye developers ultimately desired.

A still further object of the present invention is to provide novel photographic compounds, processes and products for obtaining color images by diffusion-transfer reversal processes, wherein the light absorption characteristics of the dye developers utilized to provide said color images are temporarily shifted so that said dye developers absorb actinic energy at wave lengths substantially shorter during exposure than the Wave lengths to which the dye developers associated silver halide emulsion is sensitized.

A still further object of the present invention is to provide novel photographic compounds, processes and products for obtaining multicolor transfer images, using integral multilayer photosensitive elements, whereby unwanted absorption, that is, absorption at the wave lengths of emulsion sensitization, is avoided A still further object of the present invention is to provide novel photographic processes whereby temporarily shifted dye developers, that is, dye developers the spectral absorption bands of which have been temporarily shifted to lower wave lengths prior to exposure of a photo-sensitive element containing said dye developers, may be restored to their original spectral absorption characteristics subsequent to exposure of said photosensitive element.

A still further object of the present invention is to provide dye developers, the spectral absorption characteristics :of which are modified to effect a temporary hypsochromic shift in the wave lengths absorbed during exposure of an associated photosensitive emulsion and which, subsequent to said exposure, may be restored to their original absorption characteristics.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIGURE 1 is a diagrammatic cross-sectional view of one embodiment of a photographic product for use in obtaining monochromatic images in accordance with this invention and comprising a photosensitive element, an image-receiving element and a rupturable container holding a processing composition;

FIG. 2 is a diagrammatic cross-sectional view of one embodiment of this invention, for use in obtaining multicolor images, during processing and comprising a multilayer photosensitive elemen-t, an image-receiving element and a processing composition; and

FIG. 3 is a graphic illustration of the spectral absorption characteristics of a dye developer of the present inventions preferred class including the temporarily shifted absorption curve of the modified dye developer superposed upon the absorption curve of the reconstituted, original dye developer and the corresponding curves of a closely related auxochromophoric system set forth for the purpose of providing comparative data.

The expression temporarily shifted dye developer as used herein is intended to signify a dye developer which has been modified chemically so that its spectral absorption bands have been relocated at substantially" shorter wave lengths, that is, a hypsoch-romic shift of the absorption spectrum, for at least the time interval necessary to accomplish photoexposure of a photosensitive silver halide emulsion associated therewith, and which dye developer is subject to restoration of the dye developers original absorption characteristics upon simple chemical treatment, such as, for example, hydrolysis, methanolysis, ammonolysis, etc.

It has been proposed, in the copenoing US. application of Howard G. Rogers, Ser. No. 748,421, filed July 14, 1958 (now US. Patent No. 2,983,606, issued May 9, 1961), to form color images by diffusion-transfer reversal processes utilizing dye developers. In processes of this type, a photosensitive element containing a dye developer and a silver halide emulsion is exposed and wetted by a liquid processing composition, for example, by immersion, coating, spraying, flowing, etc., in the dark, and the exposed photosensitive element is superposed prior to, during, or after wetting, on a sheetlike support element which may be utilized as an image-receiving element. In a preferred embodiment, the liquid processing composition is applied to the photosensitive element in a substantially uniform layer as the photosensitive element is brought into superposed relationship with the imagereceiving layer. The liquid processing composition permeates the emulsion to initiate development of the latent image contained therein. The dye developer is immobilized or precipitated in exposed areas as a conse quence of the development of the latent image. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation and especially as regards its solubility in alkaline solutions. It may also be due in part to a tanning effect 011 the emulsion by oxidized developing agent, and in part to a localized exhaustion of alkali as a result of development. In unexposed and partially exposed areas of the emulsion, the dye developer is unreacted and diffusible and thus provides an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition, as a function of the point-to-point degree of exposure of the silver halide emulsion. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer or element, said transfer substantially excluding oxidized dye developer. Under certain conditions, the layer of liquid processing composition may be utilized as the image-receiving layer. The imagereceiving element receives a depthwise diffusion, from the developed emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide the reversed or positive color image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. If the color of the transferred dye developer is affected by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. The desired positive image is revealed by stripping the image-receiving layer from the photosensitive element at the end of a suitable imbibi. tion period.

The dye developers, as noted above, are compounds which contain, in the same molecule, both the chromophoric system of a dye and also a silver halide developing function. By a silver halide developing function is meant a grouping adapted to develop exposed silver halide. A preferred silver halide development function is a hydroquino nyl group. Other suitable developing functions include orthodihydroxyphenyl and orthoand para-amino substituted hydroxyphenyl groups. In general, the development function includes a benzenoid developing function, that is, an aromatic developing group which forms quinonoid or quinone substances when oxidized.

The preferred dye developers possess the characteristics of relatively high absorption of actinic radiation over a desired segment of the spectral range as well as substantially no absorption over the remaining portion of the spectrum. For example, in a diffusion-transfer reversal process for three-color subtractive photography, the preferred dye developers utilized should comprise, respectively, a yellow, a magenta, and a cyan dye developer, each of said dye developers having a high transmittance over approximately two-thirds of the visible spectrum, and a high absorption in the remaining one-third.

Where such dye developers are initially colored and situated in an appropriately sensitized emulsion layer, that is, an emulsion layer sensitized to areas of the visible spectrum coinciding with the absorption maximum of the respetcive associated dye developers, it is obvious that the amount of actinic energy necessary to accomplish suitable excitation of the sensitized silver halide crystals contained within said emulsion is substantially increased.

The resultant effect of the dye developers absorption of a substantial proportion of the actinic energy available for silver halide crystal excitation is necessarily a substantial decrease in the relative speed of the associated photosensitive emulsion.

As previously stated, in multicolor photographic processes, the respective preferred dye developers should theoretically absorb actinic radiation over a selected portion of the spectral range equal to the color absorption desired and further should exert no influence on and/or absorption over the remaining portions of the spectrum. Thus, each dye developer associated emulsion layer unit, comprising a multilayer photosensitive element for use in obtaining multicolor images, should theoretically absorb spectral radiation on a predelineated area of the spectral range. Therefore, in an integral multilayer photo sensitive element, such as illustrated in FIG. 2, which comprises three appropriately sensitized silver} halide emulsions having associated therewith, respectively, a yellow, a magenta and a cyan dye developer, the preferred yellow dye developer should be one with relatively high absorption in the blue area of the spectrum and thus would affect or control only the amount of blue light passing through said dye developer but would have substantially little, if any, influence on the passage of red or green light. The magenta dye developer should be one with relatively high absorption in the green area of the spectrum and thus would affect and/or control only the amount of green light passing through said dye developer but would have substantially little, if any, influence on the passage of red or blue light. The cyan dye developer should be one with relatively high absorption in the red area of the spectrum and thus would affect or control only the amount of red light passing through said dye developer but would have substantially little, if any, influence on the passage of blue or green light.

Therefore, in an integral multilayer photosensitive element of the type previously described, upon exposure to actinic radiation comprising the visible spectrum, said radiation preferably traversing through a blue-sensitive emulsion perpendicular to the plane of said photosensitive element, the respective yellow dye developer or developers should theoretically absorb only the blue portion of the spectrum, thus allowing undiminished red and green wave lengths to contact a subsequent green-sensitive magenta dye developer containing silver halide emulsion. The magenta dye developer, in turn, should theoretically absorb only the green wave lengths of the spectrum and thus allow the red wave lengths to contact, with undiminished energy, a subsequent red-sensitive cyan dye developer containing silver halide emulsion. Many yellow, magenta and cyan dye developers exhibit substantial spectral absorption in areas of the spectrum other than their preferred theoretical areas.

The unavailability of dye developers with desired absorption characteristics, that is, over one-third of the spectrum, and desired transmission characteristics, that is, over two-thirds of the spectrum, necessitates formulating a method of preand/ or post-correcting of each emulsion layer to avoid the loss of a substantial amount of actinic energy upon exposure due to the undesirable absorption of the dye developer associated emulsion layers through which the actinic radiation must traverse in order to expose subsequent photosensitive emulsion layers.

It has been discovered that the necessity of correcting or compensating for the aforementioned undesirable absorption, that is, internal absorption within the respective emulsion layer decreasing the speed of said emulsion, as well as decreasing the actinic radiation transmitted through said emulsion, may be substantially obviated by effecting temporarily, that is, at least for the duration of exposure of a photosensitive element, a hypsochromic shift of the absorption characteristics of the respective dye developers such that the absorption of said dye developers is rendered negligible and transmission of the preferred spectral rays of light approximates the magnitude desired.

Dispersion of an associated dye developer in the photosensitive emulsion generally results in a substantial loss of the sensitivity of the emulsion due to the dye developer absorbing actinic energy in the corresponding region of maximum emulsion sensitivity. This is apparently due to the fact that photographic dye developers associated with a photosensitive silver halide emulsion generally possess a color, that is, a spectral absorption. curve, which is substantially the same as that of the light, that is, the region of the spectrum, which the sensitized emulsion is intended to record. In such instances, the dye developer has its light absorption maximum, than is A at a wave length within the maximum sensitivity of the photosensitive emulsion with which it is associated.

A hypsochromic shift of the light absorption spectrum of the respective dye developer is preferred since the absorption bands of the dye fall off more sharply on the long wave length side of the k A hypsochromic shift of the xmax, approximating 100 m substantially avoids absorption of spectral energy by the respective dye developer in the spectral region to which the associated emulsion is sensitized. However, it must be noted that a hypsochromic shift of the A approximating 20 to 30 m may substantially obviate the filtering effect of the respective dye developers absorption on photosensitive emulsions in a rearward position required by the conventional arrangement of integral multilayer photosensitive elements.

It has now been discovered that the aforementioned temporary shift of the dye developers absorption characteristics may be attained by the utilization of monoand disazo dye developers wherein the bathochromic effects of auxochromic hydroxy or amino substituted radicals substituted at specific positions in relation to the azo configuration, have been temporarily reduced by appropriately isolating said radicals from interaction with the azo chromophore.

From the standpoint of the color of dyes, an auxochrome is best defined as a substituent atom or group which increases the intensity (e) of the absorption of light due to a chromophore. An auxochrome may also shift the main absorption band (A to a longer wave length, just as a second chromophore conjugated with the first increases the e in addition to shifting it to a longer k It must be noted, however, that a given auxochrome may increase the 6 only for certain chromophores, and only when it is situated in a suitable position with reference to said chromophore, to thus form an auxochromophoric system. In an auxochromophoric system, it is believed that the absorption of light results from the electronic interaction between auxochromes and chromophores byv which the contribution of highly conjugated and polarized structures to the resonance of the dye molecule is increased.

Auxochromic hydroxyl and amino groups play a vital role in influencing the absorption characteristics of the azo dye developers of this invention by reason of electronic interaction between the azo chromophore and the respective hydroxyl or amino group. The position of the respective substituent in relation to the azo linkage largely determines the auxochromic effect; since resonance effects are inoperative in the meta position, auxochromic substituents are mainly effective in the ortho and para positions with respect to the azo chromophore.

Specifically, it has now been discovered that the previously characterized advantages achieved by the utilization of temporarily shifted dye developers, in photographic systems, may be obtained by the employment of dye developers where in the bathochromic effects of specified auxochrome components, of the selected auxochromephoric systems, may be temporarily reduced by interruption of the electronic interaction between the respective auxochromes and chromophores and, more specifically, by interruption of the last-mentioned electronic interaction between auxochromic hydroxyl or amino groups substituted in ortho and/or para position with respect to a chromophoric azo linkage, effected by any suitable technique, but, most preferably, by means of effecting temporary acylation of the respective auxochrome substituent or substituents. Restoration of the original auxochromephoric system may be then readily secured by hydrolysis of the introduced acyl group such as, for example, hydrolysis of such acyl group by means of contact with an aqueous alkaline photographic processing composition.

While the last-mentioned acylation, of the selected auxochromic substituent, does accomplish a hypsochromic shift in the spectral absorption characteristics of the selected auxochromophoric system, where the selected auxochromic substituent comprises an amino group substituted in ortho or para position with relation to a chromophoric azo linkage and/or a hydroxyl group substituted in para position to such an azo linkage, it has quite unexpectedly been found that acylation of an auxochromic hydroxyl group substituted in ortho position with relation to a chromophoric azo linkage provides a hypsochromic shift of such extended magnitude as to be totally unexpected in view of, and unrelated in comparison with, the magnitude of hypsochromic shift provided the previously identified components.

As stated hereinbefore, a temporary hypsochromic shift of the dye developers k at least for the period during which exposure of a photographic film unit retaining same is accomplished, constituting a magnitude of 20 to 30 m may be sufiicient to substantially avoid a filtering effect, in the transmission of actinic energy to a rearwardly positioned photosensitive emulsion, in many desired instances. In certain instances, therefore, acylation of a selected auxochromic amino group substituted ortho or para to a chromophoric azo linkage or, for example, a1 ternatively, acylation of an auxochromic hydroxyl group substituted para to a chromophoric azo linkage may be sufficient to provide the desired radiation absorptive characteristics to a given photographic film unit. In many instances, however, the maximum magnitude of such shift is considerably less than that required to provide the optimum radiation absorbing characteristics to the film unit. In such circumstances, it is necessary that acylation of an auxochromic hydroxyl group substituted in ortho position with respect to a chromophoric azo linkage, in accordance with the present disclosure, must be employed to provide the required photographic optical properties.

In specific illustration of the respective magnitude of the hypsochromic shift obtained by the last-mentioned procedure, and comparison with the procedure detailed immediately preceding same, reference may be made to FIG. 3 of the drawing wherein there is graphically illustrated the reduction of the bathochromic effect of a preferred auxochromophoric dye developer system, induced by temporary acylation of an auxochromic hydroxyl group substituted in ortho position with respect to a chromophoric azo configuration, and which is further graphically compared with the reduction in the bathochromic effect of a comparative auxochromophoric dye system, induced by the temporary acylation of an auxochromic hydroxyl group substituted in para position with respect to a chromophoric azo configuration. The graphic illustrations Curve A sets forth the spectral absorption curve of a preferred auxochromophoric dye developer system, that is, 2 (p-[B-(hydroquinonyl)-ethyl]-phenylazo)-4-rnethoxyl-naphthol, exhibiting a k at 529 m i, in acetone, 6: 19,800, and the graphic illustrations Curve B sets forth the spectral absorption curve of the last-mentioned dye developer specifically acylated in accordance with the instant disclosure, that is, l-acetoxy-Z-(p-[B-(hydroquinonyl) -ethyl] -phenylazo) -4-methoxy-naphthalene, eX- hibiting a a at 390 I'D/L, in acetone, e=6,700 thus illustrating, by superpositioning of the respective curves, the optical effects of the temporary modification of a preferred azo dye developer according to the instant disclosure. The graphic illustrations Curve C sets forth the spectral absorption curve of the auxochromophoric dye system (4-phenylazo-l-naphthol), exhibiting a kmax, at 410 m in methyl Cellosolve, e=16,200, and the graphic illustrations Curve D sets forth the spectral absorption curve of the last-mentioned dye system specifically acylated in accordance with the instant disclosure, that is, l-acetoxy- 4-phenylaZo-naphthalene, exhibiting a k at 374 my, in methyl Cellosolve, e=1,400, thus illustrating, by superpositioning of the respective curves, the optical effects of a temporary modification of a comparative dye system according to the disclosure detailed herein and comparison of the magnitude of the modification achieved employing the designated acylation of an auxochromic hydroxy group positioned in para relationship to a chromophoric azo group, with the magnitude of the modification obtained by the specified acylation of an auxochromic hydroxyl group in ortho position to a chromophorie azo group. It will thus be readily appreciated that the hypsochromic shift achieved by the preferred procedure of the instant disclosure, illustrated in FIG. 3 of the drawing, comprises a shift in the xmax, approximating 139 Ill 1., whereas the corresponding hypsochromic shift in the A obtained in the example detailed in FIG. 3 for comparative purposes, approximates 36 me. It should also be noted that repetition of the above procedure specifically comparing acylation of the above-identified auxochromic amino groups with the preferred system of the present disclosure will confirm the unexpected magnitude of the hypsochromic shift achieved by the instant disclosures preferred procedure.

The preferred group of dye developers, the spectral absorption curve of which may be subjected to a temporary hypsochromic shift by isolation of an appropriate auxochromic substituent, comprises monoand disazo dye developers characterized in that they contain an auxochromic hydroxyl group substituted on an aryl nucleus in ortho or ortho,ortho positions to one or both azo linkages, that is, monoand disazo dye developers characterized in that said dye developers contain not less than one and not more than two groups selected from the groups represented by the formulae:

wherein a is one or two; b is one or two; Xis a p-dihydroxyphenyl or an o-dihydroxyphenyl group and the halogen and alkyl substituted derivatives thereof; each Y represents the non n1etallic atoms necessary to complete an aryl nucleus, preferably a benzene or naphthalene nucleus, which aryl nuclei may be the same or different; and Z represents the residue of an azo coupler.

As examples of ortho-hydroxy and/or orth0,ortho-dihydroxy substituted monoand disazo dye developers preferred for use in the practice of the present invention, mention may be made of the following:

2-(4'-[4"-(2,5"-dihydroxyphenethyl)-phenylazo] naphthalene azo)-4-methoxy-1-naphthol p-(1-hydroxy-4-methoxy-2-naphthalene azo)-phenethyl catechol 2- (p- [[i- (hydroquinonyl)-ethyl] -phenylazo) -4-methoxyl-naphthol 2-(p- [B-( hydroquinonyl)-ethyl] -phenylazo -4-n-propoxy-1naphthol the preparations of which are disclosed in the copending U.S. application of Elkan R. Blout, Milton Green, and Howard G. Rogers, Ser. No. 612,045, filed Sept. 25, 1956, abandoned and replaced by Ser. No. 144,816, filed Oct. 18, 1961 (now U.S. Patent No. 3,134,672, issued May 26, 1964);

2-(2,5'-dimethoxy-4- [p-(2,5-dihydroxyphenyl)- phenylazo] -phenylazo) -4-methoxy-1-naphthol the preparation of which is disclosed in the copending U.S. application of Helen P. Husek and Myron S. Simon, Ser. No. 612,054, filed Sept. 25, 1956, now abandoned and replaced by Ser. No. 197,283, filed May 24, 1962, and Ser. No. 197,259, filed May 24, 1962 (now U.S. Patent No. 3,134,763, issued May 26, 1954);

2-(2',5-dimethoxy-4- [p-( 2",5-dihydroxyphenethyl)- phenylazo] -phenylazo -4-methoxy-1-naphtho1 the preparation of which is disclosed in the copending U.S. application of Helen P. Husek, Ser. No. 612,055, filed Sept. 25, 1956, now abandoned and replaced by Ser. No. 192,355, filed May 4, 1962 (now U.S. Patent No. 3,236,643, issued Feb. 22, 1966), and Ser. No. 192,354, filed May 4, 1962 (now U.S. Patent No. 3,134,762, issued May 26, 1954);

2- (p-[4'-rnethyl-2',5-dihydroxyphenylthioethyl]- phenylazo)-4-methoxy-1-naphthol the preparation of which is disclosed in the copending U.S. application of Milton Green and Howard G. Rogers, Ser. No. 663,905, filed June 6, 1957, noW abandoned and replaced by Ser. No. 193,326, filed May 8, 1962 (now U.S. Patent No. 3,222,169, issued Dec. 7, 1965);

2- p- 2',5 '-dihy droxyphenoxy] -phenylazo) -4-methoxyl-naphthol the preparation of which is disclosed in the copending U.S. application of Milton Green, Ser. No. 680,403, filed Aug. 26, 1957, now abandoned;

2- (p- [hydro quinonylsulfonyl] -phenylazo) -4-methoxyl-naphthol the preparation of which is disclosed in the copending U.S. application of Milton Green, Ser. No. 680,434, filed Aug. 26, 1957, now abandoned and replaced by Ser. No. 230,287, filed Oct. 12, 1962 (now U.S. Patent No. 3,230,086, issued Jan. 18, 1966);

2 (2',5-dimethoxy-3- [2"-(2,5'-dihydroxybenzoy1) ethyl] -phenylazo) -4-methoxy-1-naphthol the preparation of which is disclosed in the copending U.S. application of Elkan R. Blout, Milton Green, Howard G. Rogers, and Myron S. Simon, Ser. No. 685,081, filed Sept. 20, 1957, now abandoned and replaced by Ser. No. 222,702, filed Sept. 10, 1962 (now U.S. Patent No. 3,208,991, issued Sept. 28, 1965), and Ser. No. 222,656, filed Sept. 10, 1962 (now U.S. Patent No. 3,143,565);

2-(4'- [p-(hydroquinonyl)-phenylcarboxamido]- phenylazo) 4-methoxy-1-naphthol the preparation of which is disclosed in the copending U.S. application of Milton Green, Ser. No. 703,515, filed Dec. 18, 1957, now abandoned;

4,4'-'bis- (4"- [2"',5'-dihydroxyphenethyl] phenylsulfamyl) -1hydroxy-1,2'-azonaphthalene 4- (4'- 2",5 "-dihydroxyphenethyl] N-methyl-phenylsulfamyl) 2- 2,5 '-dimethoxyphenylazo l naphthol 2- (4'- [4"-(2"',5-dihydroxyphenethyl) -phenylcarbamyl] phenylazo) 4-methoxy-1-naphthol the preparation of which is disclosed in the copending US. application of Milton Green and Howard G. Rogers, Ser. No. 748,145, filed July 14, 1958, now abandoned and replaced by Ser. No. 190,804, filed Apr. 27, 1962 (now US. Patent No. 3,186,982, issued June 1, 1965); and

l- 4'- [2,5 "-dihydroxyphenethyl -2'-hydroxy-phenylazo) 2-naphthol the preparation of which is disclosed in the copendin US. application of Milton Green and Myron S. Simon, Ser. No. 788,893, filed Jan. 26, 1959, now abandoned and replaced by Ser. No. 359,998, filed Apr. 15, 1964.

In compounds comprising the last-mentioned class of dye developers, the auxochromic hydroxyl group may be selectively isolated from interaction with the azo chromophore by acylation of said hydroxyl group according to the following procedure, in order to provide the preferred dye developers for use in the practice of the present invention. These dye developers comprise novel monoand disazo dye developers characterized in that said dye developers contain not less than one and not more than two groups of the formula:

ortho to at least one azo group, and not more than one of said groups is ortho to the same nitrogen atom of said azo group; and which dyes may also be characterized in that they contain not less than one and not more than two groups selected from the groups represented by the formulae:

wherein each R is an alkyl group, preferably a lower alkyl group of from 1 to carbon atoms such as methyl, ethyl, propyl, butyl, etc.; and said dye developers being further characterized in that they contain not less than one and preferably not more than two groups selected from the group consisting of a p-dihydroxyphenyl and an o-dihydroxyphenyl group.

The dyes denoted by the last-identified formulae may also be defined as comprising an azo dye developer of the formulae:

wherein Y represents the atoms necessary to complete an aryl group; Z represents the atoms necessary to complete an aryl group or a radical of an azo dye coupler; one of said Y and Z contains an orthoor para-dihydroxyphenyl; and each R is an alkyl group.

It has been discovered that compounds within the aforementioned formulae may be prepared by oxidizing to the quinone the p-dihydroxyphenyl or o-dihydroxyphenyl groups or derivatives thereof of monoor disazo dyes characterized in that said dyes contain not less than one and not more than two ortho-hydroxyazo and/ or ortho, orthodihydroxyazo configurations and said dyes being further characterized in that they contain not less than one and not more than two groups selected from the group consisting of p-dihydroxyphenyl and o-dihydroxyphenyl groups and the halogen and alkyl substituted derivatives thereof, said oxidation being accomplished, for example, with an oxidizing agent such as benzoquinone, chloranil, etc.; acylating the hydroxyl groups substituted ortho and/ or ortho to one or more azo groups by reacting the oxidation product with an acylating agent, preferably an enol ester, especially an enol ester of the formula:

wherein R and R each may be the same or different and are hydrogen or an alkyl group, such as CH C H etc.; R is hydrogen, an alkyl group, such as CH nC H n-C H11, etc., an alkenyl group, such as CH3 CHs-( 3=CH or an aryl group, such as phenyl; and R is an alkyl group; said acylation preferably being accomplished either utilizing the acylating compound as the solvent medium or in an inert solvent such as methylene chloride, ethyl acetate, etc., in the presence of a suitable catalyst such as a strong inorganic acid, for example, concentrated perchloric, sulfuric, etc., acids; and regenerating the p-dihydroxyphenyl or o-dihydroxyphenyl groups or derivatives thereof by reduction, said reduction being accomplished, for example, with a reducing agent such as xylohydroquinone or hydrogen in the presence of a suitable catalyst such as a palladium/charcoal catalyst.

It is contemplated within the scope of this invention that, where desirable, the dyes may contain one or more hydroxyl groups substituted thereon in addition to those previously mentioned. Under such conditions, the acylationaction may be continued until substantially complete acylation is attained, that is, acylation of each free hydroxyl group of the respective dye molecules.

As illustrative examples of the preferred enol ester acylating agents deemed suitable for utilization in the practice of this invention, mention may be made of: 1-propen-2-ol acetate, 2-buten-2-ol acetate, 4-methyl-1,3pentadiene-Z-ol acetate,

1 1 l-phenylethanol acetate, 4-methyl-2-penten-2-ol acetate, Z-hepten-Z-ol acetate, 2-octen-2-ol acetate, 2,6-dimethyl-4-hepten-4-ol acetate, vinyl acetate, l-hexen-Z-ol acetate, l-hepten-Z-ol acetate, 1-hexen-2-ol-chloroacetate, etc.

Additional useful azo dye developers, that is, azo dye developers wherein amino groups are substituted ortho or para or wherein hydroxyl groups are substituted para to an azo linkage, may be suitably acylated by reaction withan appropriate acid chloride or anhydride, that is, acylating the respective hydroxyl or amino auxochromic group in the presence of or subsequent to effecting temporary protection of the silver halide developer imparting radicals of the aforementioned dye developers benzenoid developing group or groups.

As additional examples of acylating agents which may be employed in synthesizing the previously-detailed acylated dye developers, mention may be made of bromoacetyl bromide; chloroacetyl chloride; acetyl chloride; phenylacetyl chloride; acetyl bromide; n-butyryl chloride; propionyl chloride; iso-valeryl chloride; n-valeryl chloride; u-bromopropionyl bromide; dichloroacetyl chloride; cinnamoyl chloride; hexanoyl chloride; n-heptoyl chloride; hydrocinnamoyl chloride; iso-butyryl chloride; 4 methyl-n-valeryl chloride; crotonyl chloride; a-phenoxypropionyl chloride; phenoxyacetyl chloride; octanoyl chloride; propionyl bromide; a-ethyl-n-butyryl chloride; isobutyryl bromide; n-valeryl bromide; iso-valeryl bromide; DL-Z-methyl-n-butyryl chloride; a-bromo-iso-butyryl bromide; and the corresponding anhydrides, formates and chloroformates.

It will be recognized, from the preceding discussion, that R is intended to encompass the equivalents thereof and, accordingly, may comprise a substituted alkyl, or aliphatic, group which may be saturated or unsaturated, in accordance with the specific acylating agent optionally chosen to conform with the desires of the operator.

With specific regard to the p-dihydroxyphenyl and o-dihydroxyl groups, or radicals, the remaining hydrogen atoms in the phenyl ring system may be suitably substituted by hydroxyl groups, amino groups, alkyl groups, or halogen atoms such as chloride and bromide atoms, and the like, which do not interfere with the photographic silver halide developing characteristics of the specified dihydroxyphenyl ring system.

In accordance with the present invention, it is contem plated to utilize a temporarily shifted dye developer and, specifically, a dye developer of the preferred class detailed hereinbefore, in both monochromatic and multicolor diffusion-transfer reversal processes. It is contemplated to use at least one of the dye developers employed in multicolor diffusion-transfer reversal processes in the form of a temporarily shifted dye developer. Si nificant improvements may result from the use of even one temporarily shifted dye developer in a multicolor process. It is also contemplated to employ a plurality of temporarily shifted dye developers containing varying modifying groups to effect temporary shift of the respective dye developers spectral characteristics.

The novel temporarily shifted dye developers of the present invention also find extensive application in subtractive color correction processes, such as the integral masking procedures utilizing temporarily shifted dye developers disclosed and claimed in the aforementioned copending US. application, Ser. No. 789,080.

FIG. 1 of the accompanying drawing illustrates one method of processing a silver halide emulsion to obtain a monochromatic transfer image in accordance with this invention. A photosensitive element 22 comprises a support 20, a layer 16 containing a temporarily shifted dye developer, and a silver halide emulsion. As shown in the particular embodiment depicted in FIG. 1, the photosensitive element 22 is shown in a spread-apart relationship (as, for example, during exposure) with an image-receiving element 24 having mounted thereon a rupturable container 14 holding a processing composition. The imagereceiving element 24 comprises a support 10 and an image-receiving layer 12. After exposure, the imagereceiving element 24 is brought into superposed relationship with photosensitive element 22, rupturable container 14 is ruptured by application of suitable pressure, for example, by advancing between a pair of rolls (not shown), and a layer of the liquid processing composition is spread between the superposed elements. The processing composition permeates the silver halide emulsion and develops a latent image contained therein. Subsequent to exposure, the temporarily shifted dye developer is restored to its original spectral absorption characteristics. In unexposed areas, the dye developer will transfer to the superposed image-receiving element 24, to constitute thereon a positive dye image in terms of exposure, said image exhibiting the spectral absorption characteristics of the desired restored dye developer. The image-receiving element 24 is separated from its superposed relationship with the photosensitive element 22 after at least a portion of the dye developer has been transferred.

It should be noted that it is within the scope of the present invention to form images which comprise mixtures of temporarily shifted dye developers and non-shifted or restored dye developers. The restoration of the respective dye developers original spectral absorption characteristics may be effected by reacting said dye developer with one or more processing compositions, subsequent to photoexposure, but prior to, concurrently with or subsequently to photographic processing. If desired, a transferred dye developer containing image-receiving element may be contacted with said processing compositions subsequent to dissociation of said image-receiving element from its superposed relationship to the photosensitive element. For example, a temporarily shifted esterified dye developer containing image-receiving element, the ester components of said dye developer being difiicultly hydrolyzable, may be subjected to additional caustic hydrolysis by contact with a second hydrolytic processing composition prior to or subsequent to the aforementioned dissociation to provide an increased quantity of hydrolyzed dye developer therein.

In the following examples, all parts are given by weight except where otherwise noted and all operations involving light-sensitive materials are carried out in the absence of actinic radiation. These examples are intended to be illustrative only of the synthesis and employment of temporarily shifted dye developers wherein, subsequent to photoexposure, at least a portion of said temporarily shifted dye developer is restored to the desired substractive color absorption spectrum to provide a reversed positive transfer image of the photographed subject and should not be considered as limiting the invention in any way.

Example 1 10 gm. of 2-(p-[fi-(hy-droquinonyl)-ethyl]-phe-nylazo)- 4-methoxy-l-naphthol, the preparation of which is disclosed in the aforementioned US. Patent No. 3,134,672, and 10.5 gm. of benzoquinone are refluxed for 3.5 hours in cc. of chloroform to provide 3 gm. of

4-methoxy 2 (p-[fl-(p'-quinonyl)-ethyl]-phenylazo)-1- naphthol.

Example 2 8 gm. of 4-methoxy-2-(p-[fl-(p'quinonyl)-ethyl]-phenylazo)-l-naphthol and 25 gm. of 1-propen-2-0l acetate are dissolved in 100 cc. of ethyl acetate. 2 drops of concentrated sulfuric acid are added and the resultant solution refluxed for 2.5 hoursjThe solution is then filtered through sodium bicarbonate and the filtrate is diluted-with two volumes of hexane. The product is crystallized at 5 C. and collected by filtration.

The resultant product:

1 acetoxy-4-methoxy-2- (p- ,B- (p'-quinonyl -ethyl] -phenylazo)-naphthalene, exhibits a spectral absorption curve which displays a A at 396 m in acetone; e=6,800.

Example 3 0.3 gm. of 1-acetoxy-4-methoxy-2-(p-[B-(p'-quinonyl)- ethylJ-phenylazo)-naphthalene is dissolved in 15 cc. of

chloroform and reduced with 0.3 gm. of 2,5-xy1ohydro- 'quinone.

The resultant product:

' ii I on CH3 @orn-om -N=NK\H3 (IJH ollHa l-acetoxy 2 (p-[B-(hydroquinonyl)-ethyl]-phenylazo)- 4-methoxy-naphthalene is separated and purified by chromatographing on acetic acid washed alumina. The purified product exhibits a spectral absorption curve which displays a )t at 390 m in acetone; e=6,'700.

Example 4 Example 5 5 gm. of 2-(p-[p-(hydroquinonyl)-e-thyl]-phenylazo)- 4-n-propoxy-l-naphthol, the preparation of which is disclosed in the aforementioned US. Patent No. 3,134,672, and 6 gm. of benzoquinone are refluxed for 3.5 hours in 200 cc. of chloroform to provide 3.3 gm. of

. 0 OH H CHz-CHr-N=N@i l )CaH l-napthol.

- ethyl] phenylazo)- 1 4 Example 6 3.0 gm. (0.0062 mole) of 4-n-propoxy-2-(p-[fl-(pquinonyl)-ethyl]-phenylazo)-1-naphthol and 15 cc. of 1-propen-2-ol acetate are dissolved in 200 cc. of methylene chloride. 5 drops of concentrated sulfuric acid are added and the resulting solution refluxed for 2 hours. After cooling, the solution is poured into 200 cc. of ligroin, the product crystallized at approximately 5 C. for 24 hours and collected by filtration.

The resultant product:

1 acetoxy 4 n pr0p0xy-2-(p-[B-(p'-quin0nyl)-ethyl]- phenylazo)-napthalene, exhibits a spectral absorption curve which displays a A at 396 me in acetone; 15:6,800.

Example 7 3 gm. of 1-acet0xy-4-n-propoxy-2-(p-[fl-(pquinonyl)- ethyl]-phenylazo)-naphthalene are dissolved in 50 cc. of ethyl acetate and reduced by refluxing the solution with 3 gm. of 2,5-xylohydroquinone for 3 hours. After substantially complete reaction, the solution is filtered and the product purified by chromatographing an acetic acid washed alumina.

The resultant product:

1-acetoxy-2-(p-[fl (hydroquinonyl) ethyl]-phenylazo)- 4-n-propoxynaphthalene, exhibits a spectral absorption curve which displays a Amax, at 390 III/.4 in acetone; 6:6,700.

Example 8 1.3 gm. of 2-(p-[2,5-dihydroxyphenoxy]-phenylazo)- 4-methoxy-1-naphthol, the preparation of which is disclosed in the aforementioned copending US. application Ser. No. 680,403 (now abandoned), and 1.3 gm. of benzoquinone are refluxed for 3.5 hours in 10 cc. of chloroform. After filtering the hot solution, the filtrate is diluted with an equal volume of liquor to provide 1.0 gm. of the desired product:

4-methoxy-2-(4-[p quinonyloxy] phenylazo)-l-naphthol exhibiting a melting point at to 192 C.

Example 9 1.0 gm. of 4-methoxy-2-(p-[p'-quinonyloxyl]-phenylazo)-l-naphthol and 3.5 cc. of 1-propen-2-ol acetate is dissolved in 50 cc. of methylene chloride. 6 drops of concentrated sulfuric acid are added to the solution. After 15 the initial reaction, the solution is warmed for 15 minutes and then poured into a separatory funnel, washed with water and then washed with a saturated sodium bicarbonate solution. The resultant solution is dried over anhydrous magnesium sulfate. The solvents are removed in vacuo and the residual oil,

O-CHa l-acetoxy-4-methoxy-2-(4'-[p-quinonyloxy] phenylazo)- naphthalene, is dissolved in 15 cc. of ethyl acetate.

Example O-CHa 1-acetoxy-2-(p[2,5-dihydroxyphenoxy] phenylazo) 4- methoxy-naphthalene, exhibits a spectral absorption curve which displays a A at 409 m, in acetone; 5:9,100 and a A at 389 Ill/L in acetone; e=9,700.

Substitution of appropriate starting materials in the aforementioned examples, such as substituting one or more of the previously enumerated ortho-hydroxy and/ or ortho,ortho-dihydroxyazo dyes and/or one or more of the previously enumerated acylating agents, provides additional compounds within the previously stated generic formulae.

Example 11 A photosensitive element is prepared by coating a gelatin-coated film base with a solution comprising 3% of l-acetoxy-Z-(p[B-(hydroquinonyl) ethyl] phenylazo)- 4-methoxy-naphthalene (x 390 III/L in acetone;

5:6,700) and 4% cellulose acetate hydrogen phthalate dissolved in a 50:50, by volume, solution of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied thereon. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composiiton comprising:

Percent Sodium carboxymethyl cellulose 5.5 Sodium hydroxide 4.0 1-phenyl-3-pyrazolidone 1.2 2,5-bis-ethyleneimino-hydroquinone 0.9 6-nitrobenzimidazole 0.12

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetate-coated baryta paper which has been coated with a 4% solution of N-methoxymethyl polyhexamethylene adipamide in ethanol. After an imbibition period of approximately 1 minute, the imagereceiving element is separated and conatins a magenta. positive dye image, 2-(p-[B-(hydroquinonyl) ethyl] phenylazo)-4- methoxy-l-naphthol (A 529 m in acetone;

of the photographed subject.

Example 12 A photosensitive element is prepared, exposed and processed, according to the procedure of Example 11, wherein the image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a mixture of 3% polyvinyl alcohol and 1% polyvinyl pyrrolidone. After an imbibition period of approximately 1 minute, the image-receiving element is separated and contains a magenta positive dye image, Z-(p-[fi-(hydroquinonyl)-ethyl] phenylazo)-4-methoxy-1-naphthol, of the photographed subject.

Example 13 A photosensitive element is prepared by coating a gelatin-coated film base with a solution comprising 3% of l-acetoxy-Z-(p-[B-(hydroquinonyl) ethyl] phenylazo)- 4-n-propoxy-naphthalene (x 390 mg in acetone; =6,700) and 4% cellulose acetate hydrogen phthalate dissolved in a 50:50, by volume, solution of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied thereon. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

Percent Sodium carboxymethyl cellulose 5.0 Sodium hydroxide 3.0 l-phenyl-3-pyrazolidone 1.2 2,5-bis-ethyleneimino-hydroquinone 0.9 6-nitrobenzimidazole 0.16

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element was prepared as in Example 11. After an imbibition period of approximately 1 minute, the image-receiving element is separated and contains a magenta positive dye image, Z-(p-[fi-(hydroquinonyl)-ethyl]-phenylazo)-4-n-propoxy 1 naphthol (A 529 Hill. in acetone; e=19,800), of the photographed subject.

Example 14 A photosensitive element is prepared by coating a gelatin-coated film base with a solution comprising 3.5% of l-acetoxy 2 (p-[2',5-dihydroxyphenoxy]-phenylazo)- 4-methoxy-naphthalene (a A at 409 m in acetone; e=9,l00 and a xmax, at 389 m in acetone; 6:9,700), and 4% cellulose acetate hydrogen phthalate dissolved in a 50:50, by volume, solution of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied thereon. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

Percent Sodium carboxymethyl cellulose 4.5 Sodium hydroxide 2.0 1-phenyl-3-pyrazolidone 0.9 2,S-bis-ethyleneimino-hydroquinone 0.4 6-nitrobenzimidazole 0.12

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element was prepared as in Example 11. After an imbibition period of approximately 1 minute, the image-receiving element is separated and contains a magenta positive dye image, 2-(p-[2,5-dihydroxyphenoxy]-phenylazo)-4-methoxy-1-naphthol, of the photographed subject.

It is also contemplated to utilize in the preparation of monochromatic images, a film structure wherein the photosensitive element is coated over the image-receiving layer and the processing composition must permeate through the emulsion before reaching the image-receiving layer. A structure of this type is described, for example, in US. Patent No. 2,661,293, issued to Edwin H. Land on Dec. 1, 1953, and particularly with respect to FIG. 7 of said patent.

Multicolor images may be obtained using dye developers in diffusion-transfer reversal processes by several techniques. One such technique contemplates the use of a photosensitive silver halide stratum comprising at least two sets of selectively sensitized minute photosensitive elements arranged in the form of a photosensitive screen. Transfer processes of this type are disclosed in the copending US. application of Howard G. Rogers, Ser. No. 748,421 (now US. Patent No. 2,983,606, issued May 9, 1961), and also in the copending US. application of Edwin H. Land, Ser. No. 448,441, filed Aug. 9, 1956 (now US. Patent No. 2,968,554, issued Jan. 17, 1961). In such an embodiment, each of the minute photosensitive elements has associated therewith an appropriate dye developer in or behind the silver halide emulsion portion. In general, a suitable photosensitive screen, prepared in accordance with the disclosures of the last-mentioned copending applications, comprises minute red-sensitized emulsion elements, minute green sensitized emulsion elements, and minute bluesensitized emulsion elements arranged in side-by-side relationship in a screen pattern and having associated therewith, respectively, a cyan dye developer, :1 magenta dye developer and a yellow dye developer.

Another process for obtaining multicolor transfer images utilizing dye developers employs an integral multilayer photosensitive element such as is disclosed and claimed in the copending US. application of Edwin H. Land and Howard G. Rogers, Ser. No. 565,135, wherein at least two selectively sensitized photosensitive strata are superposed on a single support and are processed, simultaneously and without separation, with a single, common image-receiving layer. A suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. The dye developer may be utilized in the silver halide emulsion layer, for example, in the form of particles, or it may be employed as a layer behind the appropriate silver halide emulsion strata. Each set of silver halide emulsion and associated dye developer strata may be separated from other sets by suitable interlayers, for example, by a layer of gelatin and/or polyvinyl alcohol.

A multilayer photosensitive element of the type just described is illustrated in FIG. 2 of the accompanying drawings and is depicted during processing. An exposed photosensitive element 60 comprises: a support 58; a layer 54 containing a cyan dye developer and a red-sensitive silver halide emulsion; a layer 50 of a magenta dye developer exhibiting a temporarily shifted spectral absorption curve and a green-sensitive silver halide emulsion; a layer 46 containing a yellow dye developer and a bluesensitive silver halide emulsion. As noted above, each set of silver halide emulsion and associated dye developer strata may be separated from other sets thereof by suit able interlayers (not shown), for example, by a layer of gelatin and/or polyvinyl alcohol. In certain instances, it may be desirable to incorporate a yellow filter in front of the green-sensitive emulsion and such yellow filter may be incorporated in an interlayer. However, Where desirable, a yellow dye developer of the appropriate spectral characteristics and present in a state capable of functioning as a yellow filter may be employed. In such instances, a separate yellow filter may be omitted.

Referring again to FIG. 2, a multilayer photosensitive element 60 is shown in processing relationship with an image-receiving element 62 and a layer 44 of a processing composition. The image-receiving element 62 comprises a support 40 and an image-receiving layer 42. As noted in connection with FIG. 1., the liquid processing composition is effective to initiate development of the latent image in the respective exposed silver halide strata and also may effect restoration of the respective temporarily shifted magenta dye developer to its original absorption characteristics. After a suitable imbibition period, during which at least a portion of the dye developer associated with unexposed areas of each of said emulsions is transferred to the superposed image-receiving element 62, the latter element may be separated to reveal the positive multicolor image.

It should be noted that it is within the scope of this invention to utilize, in multicolor diffusion-transfer reversal processes, one or more of the requisite dye developers in the form of temporarily shifted dye developers. In certain instances, for example, it may be desirable to employ temporarily shifted dye developers in association with a red-sensitive and green-sensitive silver halide emulsion, together with a non-shifted dye developer associated with the blue-sensitive silver halide emulsion.

A further technique for obtaining multicolor images employs a plurality of photosensitive elements associated with an appropriate number of image-receiving elements and adapted to be treated with one or more liquid processing com-positions, the appropriate dye developers being incorporated in the photosensitized elements. Examples of film structures of this type are disclosed in US. Patent No. 2,647,049, issued to Edwin H. Land on July 28, 1953.

The dye developers utilized in the processes of this invention may be incorporated in the photosensitive elements, for example in, on, or behind the respective silver halide emulsion. The dye developer may, for example, be in a coating or layer behind the silver halide emulsion and such a layer of dye developer may be applied by the use of a coating solution containing about 0.5 to 8%, by Weight, of the respective dye developer. When the temporarily shifted dye developers, set forth in Examples 1 and 2, were placed in a dye carrier layer behind the greensensitive emulsion in an integral multilayer photosensitive element of the type described in connection with FIG. 2, sensitivity of the rearwardly positioned red-sensitive emulsion was extended approximately30 m into the shorter wave lengths of the spectrum, that is, the sensitivity of the red-sensitive emulsion was extended from approximately 640 me down to approximately 610 m The liquid processing composition herein referred to comprises at least an aqueous solution of an alkaline cornpound, for example, diethylamine, sodium hydroxide or sodium carbonate. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin uniform layer, it may also include a viscosity-increasing compound constituting a film-forming material of the type which, when said composition is spread and dried, forms a relatively firm and relatively stable film. A preferred film-forming material is a high molecular weight polymer such as a polymeric, water-soluble ether which is in inert to an alkaline solution such as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials or thickening agents whose ability to increase viscosity is substantially unaffected if left in solution for a long period of time may also be used. The film-forming material is preferably contained in the processing complications herein mentioned and also in examples herein given. Under certain circumstances, it may be desirable to apply a liquid processing composition to the photosensitive element prior to exposure, in accordance with the technique described in the copending U.S. application of Edwin H. Land, Ser. No. 498,672, filed Apr. 1, 1955 (now U.S. Patent No. 3,087,816, issued Apr. 30, 1963).

It will be noted that the liquid processing composition employed may contain an auxiliary or accelerating developing agent, such as p-methylaminophenol, 2,4-diam.- inophenol, p-benzylaminophenol, hydroquinone, toluhydroquinone, phenylhydroquinone, 4-methylphenylhydroquinone, etc. It is also contemplated to employ a plurality of auxiliary or accelerating developing agents, such as a 3-pyrazolidone developing agent and a benzenoid developing agent, as disclosed in U.S. Patent No. 3,039,869, issued June 19, 1962. As examples of suitable combinations of auxiliary developing agents, mention may be made of 1-phenyl-3-pyrazolidone in combination with p-benzylaminophenol and 1-phenyl-3-pyrazolidone in combination with 2,5-bis-ethyleneimino-hydroquinone. Such auxiliary developing agents may be employed in the liquid processing composition or they may be initially incorporated, at least in part, in the silver halide emulsion strata or the strata containing the dye developers. It may be noted that at least a portion of the dye developer oxidized during development may be oxidized and immobilized as a result of a reaction, e.g., an energy-transfer reaction, with the oxidation product of an oxidized auxiliary developing agent, the latter developing agent being oxidized by the development of exposed silver halide. Such a reaction of oxidized developing agent with unoxidized dye developer would regenerate the auxiliary developing agent for further reaction with the exposed silver halide.

In addition, development may be effected in the presence of an onium compound, particularly a quaternary ammonium compound, in accordance with the processes disclosed in the copending U.S. application of Milton Green and Howard G. Rogers, Ser. No. 50,851, tiled Aug. 22, 1960 (now U.S. Patent No. 3,173,786, issued Mar. 16, 1965).

The dye developers are preferably selected for their ability to provide colors that are useful in carrying out subtractive color photography, i.e., cyan, magenta and yellow. It should be noted that it is within the scope of this invention to use mixtures of dye developers to obtain a desired color, e.g., black. Thus it is to be understood that the expression color as used herein is intended to include the use of a plurality of colors to obtain black, as well as the use of a single black dye developer.

In all products employed in the practice of this invention, it is preferable to expose from the emulsion side. It is, therefore, desirable to hold the photosensitive element and the image-receiving element together at one end thereof by suitable fastening means in such manner that the photosensitive element and the image-receiving element may be spread apart from their superposed processing position during exposure. A camera apparatus suitable for processing film of the type just mentioned is provided by the Polaroid Land Camera or similar camera structure such, for example, as the roll film-type camera forming the subject matter of U.S. Patent No. 2,435,717 or the film pack-type camera forming the subject matter of U.S. Patent No. 2,991,702. Camera apparatus of this type permits successive exposure of individual frames of the photosensitive element from the emulsion side thereof as well as individual processing of an exposed frame by bridging said exposed frame into superposed relation with a predetermined portion of the image-receiving element while drawing these portions of the film assembly between a pair of pressure rollers which rupture a container associated therewith and effect the spreading of the processing liquid released by rupture of said container, between and in contact with the exposed photosensitive frame and the predetermined, registered area of the image-receiving element.

The nature and construction of rupturable containers such as that shown in FIGURE 1 is well understood in the art; see, for example, U.S. Patent No. 2,543,181, issued to Edwin H. Land on Feb. 27, 1951, and U.S. Patent No. 2,634,886, issued to Edwin H. Land on Apr. 14, 1953.

The image-receiving element comprises an image-receiving layer of opaque or transparent material which is liquid permeable and dyeable from alkaline solutions and which has been illustrated for purposes of simplicity as comprising a single sheet of permeable material, for example, paper. This element, however, may comprise a support upon which at least one liquid-permeable and dyeable layer is mounted. The support layer may have a water-impermeable subcoat over which the stratum of permeable and dyeable material is applied. In certain instances, the dyeable layer may comprise a layer of liquid processing composition which is adapted to remain adhered to the support layer upon stripping.

As examples of useful image-receiving materials, mention may be made of nylon, e.g., N-methoxymethyl-polyhexamethylene adipamide, polyvinyl alcohol, and gelatin, particularly polyvinyl alcohol or gelatin containing a dye mordant such as poly-4-vinylpyridine, and other materials of a similar nature, as is well known in the art. The image-receiving element also may contain a development restrainer, e.g., 1-phenyl-5-mercaptotetrazole, as disclosed in the copending application of Howard G. Rogers and Harriet W. Lutes, Ser. No. 50,849, filed Aug. 22, 1960, and now U.S. Patent No. 3,265,498.

While a rupturable container, such as container 14 in FIGURE 1, provides a convenient means for spreading a liquid processing composition between layers of a film unit whereby to permit the processing to be carried out within a camera apparatus, the practices of this invention may be otherwise effected. For example, a photosensitive element, after exposure in suitable apparatus and while preventing further exposure thereafter to actinic light, may be removed from such apparatus and permeated with the liquid processing composition as by coating the composition on said photosensitive element or otherwise wetting said element with the composition following which the premeated, exposed photosensitive element, still without additional exposure to actinic light, is brought into contact with the image-receiving element for image formation in the manner heretofore described.

It is also to be understood that the invention may be successfully practiced without the use of a film-forming material in the liquid processing composition. As an illustration, a non-viscous liquid processing composition is particularly applicable with the processing technique last mentoned above and may be applied to the exposed photosensitive element by imbibition or coating practices and may be similarly applied to the image-receiving element before said elements are brought into superposed relation or contact for carrying out the transfer of non-immobilized color-providing substances.

It will be apparent that the relative proportions of the agents of the diffusion transfer processing composition may be altered to suit the requirements of the operator. Thus, it is within the scope of this invention to modify the herein described developing compositions by the substitution or addition of preservatives, alkalies, silver halides, solvents, etc., other than those specifically mentioned. When desirable, it is also contemplated to include, in the developing composition, components such as restrainers, accelerators, etc. Similarly, the concentration of various components may be varied over a wide range and, when desirable, adaptable components may be disposed in the photosensitive element, prior to exposure, in a separate permeable layer of the photosensitive element and/or in the photosensitive emulsion.

In all examples of this specification, percentages of components are given by weight unless otherwise indicated.

Throughout the specification the expression positive image has been used. This expression should not be interpreted in a restrictive sense since it is used primarily for purposes of illustration, in that it defines the image produced on the image-carrying layer as being reversed, in the positive-negative sense, with respect to the image in the photosensitive element. As an example of an alternative meaning for positive image, assume that the photosensitive element is exposed to actinic light through a negative transparency. In this case, the latent image in the photosensitive element will be a positive and the image produced on the image-carrying layer will be a negative. The expression positive image is intended to cover such an image produced on the image-carrying layer.

The dye developers of this invention may be used also in conventional photographic processes, such as tray or tank development of conventional photosensitive films, plates or papers to obtain black and White, monochromatic or toned prints 'or negatives. By way of example, a developer composition suitable for such use may comprise an aqueous solution of approximately 1 to 2% of the dye developer, 1% sodium hydroxide, 2% sodium sul-fite and 0.05% potassium bromide. After development is completed, any unreacted dye developer is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in Which the unreacted dye developer is soluble. The expression toned is used to designate photographic images wherein the silver is retained with the precipitated dye, whereas monochromatic? is intended to designate dye images free of silver.

Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted and not in a limiting sense.

22 What is claimed is: 1. An azo dye selected from the group consisting of azo dye developers of the formulae:

wherein Y represents the atoms necessary to complete an aryl group; Z represents the atoms necessary to complete a group selected from the group consisting of an aryl group and a radical of an azo dye coupler; one of said Y and Z contains a group selected from the group consisting of an ortho-dihydroxyphenyl and a para-di- 'hydroxyphenyl group; and each R is an alkyl group.

2. A dye developer as defined in claim 1 wherein each R is a lower alkyl group.

3. l-acetoxy-Z-(p-[B-(hydroquinoyl)-ethyl] phenylazo)-4-methoxy-naphtha lene.

4. l-acetoxy-Z-(p-[fl-(hydroquinonyl) -ethyl] phenylazo -4-n-propoxy-naphthalene.

5. l-acetoxy-Z-(p-[2',5'-dihydroxyphenoxy] phenylazo) -4-methoxy-naphthalene.

References Cited FOREIGN PATENTS 554,935 8/ 1957 Belgium.

CHARLES B. PARKER, Primary Examiner.

JOSEPH P. B'RUST, Examiner.

FLOYD D. :HIGEL, Assistant Examiner. 

1. AN AZO DYE SELECTED FROM THE GROUP CONSISTING OF AZO DYE DEVELOPERS OF THE FORMULAE: 